Resilience Audit

Verify graceful degradation and state recovery capabilities.

Purpose

Ensure the application handles adverse conditions gracefully:

• Network outages
• Server errors
• Browser crashes
• Slow connections
• Interrupted operations

Checks Performed

1. Offline Capability

2. State Recovery

3. Network Resilience

4. Data Sync

Usage

# Full resilience audit
./scripts/resilience-audit.sh

# Offline focus
./scripts/resilience-audit.sh --scope offline

# With network simulation
./scripts/resilience-audit.sh --simulate

Output Format

## Resilience Audit Report

**Date:** 2025-01-20

### Offline Capability

| Feature | Offline Status | Notes |
|---------|----------------|-------|
| View cards | ✅ Works | Cached in IndexedDB |
| Create card | ⚠️ Partial | Queued but no feedback |
| Search | ❌ Fails | Requires server |
| Settings | ✅ Works | Local storage |

### State Recovery

| Scenario | Status | Notes |
|----------|--------|-------|
| Page refresh | ✅ | URL state preserved |
| Form in progress | ⚠️ | Lost on refresh |
| Crash recovery | ❌ | No draft persistence |
| Tab sync | ✅ | Real-time sync works |

### Network Resilience

| Condition | Tested | Result |
|-----------|--------|--------|
| Offline indicator | ✅ | Shows banner |
| Retry button | ⚠️ | Only on some errors |
| Request timeout | ✅ | 30s with feedback |
| Exponential backoff | ❌ | Fixed 5s retry |

### Data Sync

| Check | Status |
|-------|--------|
| Sync queue visible | ❌ No UI |
| Conflict resolution | ✅ Last-write-wins |
| Offline queue persisted | ✅ IndexedDB |
| Sync on reconnect | ✅ Automatic |

### Recommendations

1. **HIGH**: Add draft persistence for forms
2. **HIGH**: Implement exponential backoff for retries
3. **MEDIUM**: Show pending sync count to users
4. **MEDIUM**: Add offline-capable search with local index
5. **LOW**: Add conflict resolution UI for complex cases

Resilience Patterns

Offline-First Architecture

┌─────────────────────────────────────────┐
│              Application                │
├─────────────────────────────────────────┤
│  ┌─────────┐  ┌─────────┐  ┌─────────┐ │
│  │ UI Layer│──│ Service │──│  Sync   │ │
│  │         │  │ Worker  │  │ Manager │ │
│  └─────────┘  └─────────┘  └─────────┘ │
│       │            │            │       │
│  ┌─────────────────────────────────────┐│
│  │           IndexedDB                 ││
│  │     (Source of Truth)               ││
│  └─────────────────────────────────────┘│
└─────────────────────────────────────────┘
                    │
              [Network]
                    │
              ┌─────────┐
              │ Server  │
              └─────────┘

State Recovery Strategy

Retry Strategy

// Exponential backoff with jitter
const retryDelays = [1000, 2000, 4000, 8000, 16000];
const jitter = Math.random() * 1000;
const delay = retryDelays[attempt] + jitter;

Prerequisites

• Service Worker support
• IndexedDB for offline storage
• Network Information API (optional)

See Also

• Performance Audit
• Security Audit
• Audit Framework